BLUEGREY CARPETSHARK OR COLCLOUGH’S SHARK
A rare shark with functioning eyelids that can live out of water for long periods of time
The Bluegrey carpetshark or Colcloughs shark (Heteroscyllium colcloughi) is a rare to uncommon species of Blind shark endemic to shallow inshore waters off northeastern Australia. It is one of the two extant members of the family Brachaeluridae belonging to the order Orectolobiformes. The Bluegrey carpetshark has a stocky body with a wide, slightly flattened head, dorsally placed eyes, and a pair of long barbels with posterior skin flaps. When removed from the water, the Bluegrey carpetshark will close its eyes like the related Blind shark.
Family: Brachaeluridae – Blind Sharks
Common Name– Carpet Sharks
Common Name– Blind Sharks
Status: IUCN Red List VULNERABLE
Average Size and Length: They are born between 17-18 cm. Mature males have been measured at 1.6 feet and Mature females at 2.1 feet The maximum recorded length is over 2.5 feet.
Current Rare Mythical Sightings: The Bluegrey carpetshark was described by Australian ichthyologist James Douglas Ogilby as a species of Brachaelurus, in a 1908 issue of Proceedings of the Royal Society of Queensland. He named the shark after his friend John Colclough, and based his account on two immature males about 46 cm/ 18 inches long from Moreton Bay in Queensland, one of which was later “accidentally destroyed”. The genus Heteroscyllium is a synonym of Brachaelurus.
In 1940, Gilbert Percy Whitley published the first illustrations of the Bluegrey carpetshark, but were inaccurate, particularly on omitting a midline groove on the chin. Much taxonomic confusion then resulted, on whether the Bluegrey carpetshark and the Blind shark belonged to separate genera or even constituted separate species, that were not resolved until the Queensland Museum obtained new specimens for study.
Teeth and Jaw: The mouth is short, small and almost transverse. Similar to its other family member, the tooth rows number 32–34 in the upper jaw and 21–29 in the lower jaw. Each tooth has an upright, awl-like central cusp and two lateral cusplets.
Head: It has a slightly flattened head. The snout is blunt and looks wedge-shaped from the side. The nostrils are preceded by a pair of long barbels, which have an enlarged posterior flap halfway along their lengths. There are well-developed skin flaps and grooves around the incurrent nostril opening, as well as a pair of grooves connecting them to the small, almost transverse mouth. The mouth is ahead of the eyes. The large eyes are horizontally oval and placed high on the head, each with a strong ridge underneath and a large, large round spiracles following immediately behind and below.
Denticles: The dermal denticles are tiny, smooth, and non-overlapping.
Tail: There is a short precaudal tail and caudal fin. The caudal fin is long and low and comprises about a quarter of the total length, with no lower lobe and a strong ventral notch near the tip of the upper lobe.
Demographic, Distribution, Habitat, Environment and Range: The Bluegrey carpetshark can be found in east Australia. They have been found from Gladstone, Queensland to Ballina, New South Wales, with most records coming from Moreton Bay. There are also a handful of reports from off the Cape York Peninsula, and this species may be more widely distributed on the Great Barrier Reef. They are found at the bottom in very shallow inshore areas, typically less than 20 feet. They may have been found as deep as 330 feet and even spotted in a shipwreck. They are considered demersal.
Diet: It more than likely feeds on benthic invertebrates and bony fish.
Ram-Suction Index: They are high on the suction index. Prey is captured by sucking it into their mouths with a powerful suction force.
Aesthetic Identification: The Bluegrey carpetshark is greyish above and counter-shaded white ventrally. There are no light spots. There are conspicuous black markings on the back, the dorsal fins and the caudal fin of the young which fade when they are adults. They are small and stout. The five pairs of gill slits are short, with the fourth and fifth pairs more closely spaced than the others. There are two spineless dorsal fins. The first dorsal fin is larger and it originates over the pelvic fin bases. The anal fin is less than half the size of the first dorsal fin and placed so that its free rear tip just reaches the base of the caudal fin. There is a sizable space between the anal fin and the base of the caudal fin. The pectoral and pelvic fins are broad and rounded, with the pectoral fins larger than the pelvic fins.
Biology and Reproduction: They are more than likely ovoviviparous, having 6-8 pups per litter.
Behavioral Traits, Sensing and Intelligence: Their behavior is unknown. When removed from the water, the Bluegrey carpetshark will close its eyes like the related Blind shark.
Speed: More than likely they are considerably slow like their family member.
Bluegrey Carpetshark Future and Conservation: They are listed as vulnerable because they are only known from 20 specimens in a small, well-surveyed area heavily used by fisheries and for recreation so they are presumed rare. It is taken in small numbers by commercial and recreational fisheries, and for the aquarium trade. They adapt well in captivity.
Bluegrey Carpetshark Recorded Attacks on Humans: It is harmless to humans.